The objective of this research is to better understand the hormonal control of primate corpus luteum function. The studies proposed herein are designed to investigate the role of protein kinase C. an essential component of the phosphoinositide signal-transduction system, in the hormonal control of the primate corpus luteum. In a practical sense, the knowledge gained from these studies will increase our understanding of the regulation of the menstrual cycle and enhance our ability to modulate fertility and infertility in women. The specific aims of this proposal are: 1.) To develop assays to examine hormonal stimulation of protein kinase C in the rhesus monkey corpus luteum; 2.) To determine whether hormones which are known to play a role in the control of the primate corpus luteum, and hormones for which such a role has been suggested, are able to stimulate (or inhibit) protein kinase C in the rhesus monkey corpus luteum; and, 3.) To correlate the effects of these hormones on protein kinase C activity with the functional capacity of the corpus luteum throughout the luteal phase. Three assays will be developed to examine the hormonal activation of protein kinase C in the primate corpus luteum. The first of these will examine the translocation of protein kinase C from the cytosol to the membrane fraction upon hormonal stimulation. The second will utilize polyacrylamide gel electrophoretic analysis of endogenous proteins phosphorylated by protein kinase C in response to hormonal stimulus. The third assay will involve immunohistochemical localization of protein kinase C in the primate corpus luteum. Using these assays, the hormones LH and CG, prostaglandins F2alpha, E2, I2, and D2, oxytocin, opioid peptides, catecholamines, and GnRH will be assessed for stimulatory or inhibitory effects on protein kinase C activity. Assay development and hormone studies will initially utilize tissues from midluteal phase. Since the corpus luteum is a dynamic tissue which changes markedly in function throughout the luteal phase, enzyme response to specific hormones will be assessed at various times during the luteal phase and correlated with physiological activity.